Front diff gone bad? Really?

**B6 S4 is BRZRKR** · 12-31-2009 12:08 PM

I just bought, as in this week, a 2004 (build date 09/03) 6speed Avant.

When I turn the wheels 95% going slowly (of course) in the dry, it groans. In the wet, when the tires have no traction, it hops the front wheels. Makes me think that the front diff is locked up. Thoughts? if this is the case, where do I go?

HELP!

Thanks much.

Jared

**nimski62** · 12-31-2009 12:23 PM

Normal. Search. Nuff' said.

**floorman** · 12-31-2009 12:28 PM

It's the 4wd. It's normal don't worry about it. We all have it.

**B6 S4 is BRZRKR** · 12-31-2009 12:35 PM

I bought an S4 new in 2004. Didn't do it at all. Also, I've searched "front groan" and "front diff" and find nothing. I'll keep searching terms that I can think of. Thanks for the help, guys.

**hayasa** · 01-01-2010 02:22 PM

S4 has an open front and rear diffs, but electronically controlled through stability control. The slight groaning is the center diff since it is mechanical. Normal sound.

**nycats4** · 01-01-2010 03:02 PM

Search "quattro binding" and you'll have your answer.

**Audi0s** · 01-02-2010 08:49 AM

I saw a bulletin lately that required you to overfill the power steering reservoir by 10mm to quell groaning noises. I have noticed an intermittent groan only while the clutch is down and turning the wheel, like a 3 point turn. Why theyd be related I have no idea.

**B6 S4 is BRZRKR** · 01-02-2010 09:21 AM

Thanks guys. I'll check it out. However, in response to the "we all deal with it" stuff, I'm not a noob with this. I think this is more than normal. My 04 S4 Sedan didn't do it. My Q7 4.2, A6 4.2, 4Motion Passat V6... none have this issue like this. It pops LOUDLY in a parking lot so that people turn to look. I'll read the posts though. Thanks for all the help.

**B6 S4 is BRZRKR** · 01-12-2010 09:49 AM

Flushed it (front/center diffs/trans) with Motul yesterday. Still has the problem. I also have a leak of engine or trans oil where the bellhousing meets the block. I don't know if it's the rear main seal or the equivalent in the front of the trans, but I guess I'll be doing both at once, and at the same time, I might as well upgrade the clutch, flywheel, and center diff to 4:1. Any other ideas?

**Abwasserleitung** · 06-23-2010 04:27 PM

I understand the theory behind what is happening with the mechanical diff, I've driven numerous audi's w/ quattro and none of them have groaned. I too find it hard to believe that this is normal and just go on my merry way. I am sure most of us felt this way in regards to oil consumption and Audi's response. I've talked to a few people where this was solved by replacing either the transfer case, UCA bearings, steering rack, and/or wheel bearings. I am just looking for a better answer than its normal.
Where's the facts?
i.e. problem => solution

**koolade9** · 06-23-2010 05:27 PM

There's three things being talked about here...

1. groaning while turning due to power steering - Different issue that what the OP described, as he can feel wheels hopping.
2. groaning (from the rear wheels) - due to the center diff sending more torque to the rear wheels at low speed...coincidentally, those are also the wheels moving the least when turning at full lock at low speed. - This is what's considered normal. 07 cars and newer (perhaps some 06s as well) have a different diff with a higher rear bias and this is more evident.
3. If you're turning and you hear loud "pops", then you may be looking at bad CV joints... If it was the diff, you'd most likely hear it while going straight or under light turning as well...

**audi-s** · 06-24-2010 10:15 AM

Originally Posted by koolade9

There's three things being talked about here...

2. groaning (from the rear wheels) - due to the center diff sending more torque to the rear wheels at low speed...coincidentally, those are also the wheels moving the least when turning at full lock at low speed. - This is what's considered normal. 07 cars and newer (perhaps some 06s as well) have a different diff with a higher rear bias and this is more evident.

I have this behavior/scenario on a somewhat regular basis. Dealer said the "noise" is coming from the the exhaust ?!?
Is there any "official" word - or "proof" - that this noise is really from the center diff?
Do we have an official response from AoA on this? Would be nice to have - to ease our concerns.
When "quattro binding" is mentioned to the dealer they look at you like a startled deer in front of headlights... ??

**koolade9** · 06-24-2010 10:22 AM

Originally Posted by audi-s

I have this behavior/scenario on a somewhat regular basis. Dealer said the "noise" is coming from the the exhaust ?!?
Is there any "official" word - or "proof" - that this noise is really from the center diff?
Do we have an official response from AoA on this? Would be nice to have - to ease our concerns.
When "quattro binding" is mentioned to the dealer they look at you like a startled deer in front of headlights... ??

Well, if you talk to any A4 or early S4 owner who did the 4:1 mod on their center diff, they can attest to this change in behavior. I noticed it right away, then confirmed is again with the stock RS diff.

**mbgt72** · 06-24-2010 11:25 AM

Originally Posted by koolade9

Well, if you talk to any A4 or early S4 owner who did the 4:1 mod on their center diff, they can attest to this change in behavior. I noticed it right away, then confirmed is again with the stock RS diff.

Yea I noticed a pretty big difference going to the later model center diff. Definitely the way it should of come from the getgo!

**audi-s** · 06-24-2010 09:18 PM

Originally Posted by koolade9

Well, if you talk to any A4 or early S4 owner who did the 4:1 mod on their center diff, they can attest to this change in behavior. I noticed it right away, then confirmed is again with the stock RS diff.

Thanks for the clarification!